JPS61296218A - Apparatus for detecting liquid level - Google Patents

Abstract

PURPOSE:To enable the continuous detection of a liquid level by one magnetoelectric converter element, by converting a liquid level to the distance from the magnetoelectric converter element to a magnetized body and performing the detection of the liquid level on the basis of the output of the magnetoelectric converter element. CONSTITUTION:A float 1 is mounted to a cylindrical magnetized body 2 so as to be eccentric to the revolving fulcrum part 4 of the magnetized body 2 and revolves according to the liquid level of a received liquid 6. A magnetoelectric converter element (hole IC)7 is present outside a tank 5 and, when the float 1 is revolved, the magnetized body 2 rotates and, therefore, the distance from the hole IC7 to the surface of the magnetized body 2 changes corresponding to the liquid level. The signal of the hole IC7 is outputted to a processing part 8 while output voltage inversely proportional to the distance from the surface of the magnetized body 2 is obtained from the hole IC7. Therefore, by processing output voltage by the processing part 8, the liquid level can be continuously detected by one magnetoelectric converter element.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a liquid level detection device that detects liquid level using magnetic means, and is particularly suitable for use in cartridge tanks of petroleum equipment.

2. Prior Art A conventional liquid level detection device using this type of magnetic means is the seventh
As shown in the figure, the 70-ton 1 rises and falls according to the increase and decrease of the liquid level.
A lift actuator 3 is provided with a magnet 2, and a plurality of reed switches SL, S, 2, S3, S4 and S'1, S
'2, S'3, S'4, and a resistor H interposed between the reed switches.
1, S2, S3, and S4 have their contacts sequentially opened when the lift actuator 3 passes downward, and their contacts open sequentially when the actuator 3 passes upward, and the reed switch groups S'1, S'2, and S4 '3 and S'4, on the other hand, sequentially open the contacts when the actuator 3 passes upward, and open the contacts sequentially when the actuator 3 passes downward, and each reed switch has a self-holding function. .

The liquid level was detected by applying a constant voltage between A and 0 and measuring the voltage between B and 0.

(For example, Publication No. 1'859-36212) Problems to be Solved by the Invention However, with the above configuration, 2n reed switches are required to detect the liquid level in n stages. In order to improve the detection accuracy, many reed switches are required, making it difficult to miniaturize.

Means for Solving the Problems In order to solve the above problems, the liquid level detection device of the present invention has the following features:
A magnetoelectric conversion element, a float that moves according to increases and decreases in liquid level, a magnetized body whose distance from the magnetoelectric conversion element changes as the 70-t moves, and processes an output signal of the magnetoelectric conversion element. It is constructed from a processing section that performs the following steps.

Effect The present invention has the above-mentioned configuration, and according to the change in the liquid level, the
The distance between the magneto-electric transducer and the magnet changes as the 70-toe moves, and the liquid level is detected by the output of the magneto-electric transducer, so one magneto-electric transducer can detect continuous liquid. This makes surface detection possible.

Embodiments Hereinafter, embodiments of the present invention will be explained based on the accompanying drawings. In the description of the embodiment, the same parts as in FIG. 7 are given the same numbers.

In FIG. 1, 1 is a float, and 2 is a magnetized body, which has a cylindrical shape and is eccentrically attached to the rotation fulcrum 4 of the float 10. 5 is a tank, 6Vi is a liquid content, and the float 1 rotates according to the liquid level of the liquid content 6.

There is a magnetoelectric conversion element (hereinafter referred to as Hall IC) 7 outside the tank 5, and when the float 1 rotates, a cylindrical magnetized body 2
As the magnet rotates, the distance from the Hall IC 7 to the surface of the magnetized body 20 changes depending on the liquid level. The signal from the Hall IC 7 is output to the processing section 8.

Figure 2 shows the relationship between the distance from the magnetized body and the magnetic flux density. An example of a magnetized body is a manganese aluminum magnet (010XL10
). Next, the characteristics of the Hall IC 7 are shown in FIG. Since the Hall IC 7 is a linear type and can obtain an output voltage that is approximately proportional to the magnetic flux density, as shown in Figures 2 and 3, the Hall IC 7 has an output voltage that is approximately inversely proportional to the distance from the surface of the magnetized body 2. can get. Therefore, by processing this output voltage in the processing section 8, it is possible to detect the liquid level. FIG. 4 shows an example of a specific circuit diagram of the processing section 8. Figure 84 is a circuit diagram that detects the liquid level in five stages and displays it by lighting with a light emitting diode. 9-14
is a resistor and is used to determine the comparison voltage.

15 to 19 rfiJt comparators compare the output voltage of the Hall IC 7 and the comparison voltage described above. Numerals 20 to 24 are light emitting diodes which are turned on and off according to the outputs of comparators 15 to 17. 25 to 29 are resistors for limiting the current. In the above configuration, the Hole C7 is disposed outside the tank, but even if it is disposed inside the tank, exactly the same effect can be obtained.

Next, another embodiment of the present invention is shown in FIG. The difference from the embodiment described above is that the float 1 does not rotate but moves up and down, but in this case as well, the same effect as in the embodiment described above can be obtained.

Effects of the Invention As described above, the liquid level detection device of the present invention provides the following effects.

(1) The liquid level is converted to the distance from the magnetoelectric conversion element to the magnetized object, and the liquid level is detected by the output of the magnetoelectric conversion element, so the liquid level can be continuously detected with one magnetoelectric conversion element. This has the effect of enabling compact and highly accurate liquid level detection.

2. Since the magnetoelectric transducer does not need to come into direct contact with the liquid, it is possible to indirectly detect the liquid level without incorporating electrodes or signal lines into the liquid storage tank, improving the reliability of the device. Another advantage is that it can electrically detect the liquid level in tanks that are removable, such as cartridge tanks for petroleum equipment.

a. Even if there is dust or the like between the magnetized body and the magnetoelectric transducer, it does not affect the output of the magnetoelectric transducer, so there are fewer restrictions on the installation location.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view of a liquid level detection device showing an embodiment of the present invention, Fig. 2 is a characteristic diagram of a magnetized body, and Fig. 3 is a characteristic diagram of a linear type Hall IC. Fig. 44 is a circuit diagram showing an example of the processing section of the liquid level detection device, Fig. 5 is a vertical sectional view of a liquid level detection device showing another embodiment of the present invention, and Fig. 6 is a conventional liquid level detection device. It is a circuit block diagram between bags. 1...70-t, 2...magnetized body, 7.
. . . Magnetoelectric conversion element, 8 . . . Processing section. Name of agent: Patent attorney Toshio Nakao and 1 other person7.
・Shizu 1L no history Jou 1shin d...Processing department 2nd ward Ukeishi 4° Hook box hammer L (Ryuu 3rd figure stone - Higashihiroro B (end of 4 figure 5

Claims (3)

[Claims] (1) A magnetoelectric transducer, a float that moves according to increases and decreases in liquid level, a magnetized body whose distance from the magnetoelectric transducer changes as the float moves, and processes the output signal of the magnetoelectric transducer. A liquid level detection device consisting of a processing section. (2) The liquid level detection device according to claim 1, wherein the float is rotatable, and the magnetized body is cylindrical and eccentrically provided at the rotation fulcrum of the float. (3) The liquid level detection device according to claim 1, wherein the float and the magnetized body are provided inside a liquid storage tank, and the magnetoelectric conversion element is provided outside the tank.